1. Field of the Invention
The present invention relates to a piston valve assembly for a shock absorber, which is capable of improving a ride comfort by providing a damping force sensitive to both a pressure and a frequency, and more particularly, to a piston valve assembly for a shock absorber, in which an inlet hole is formed in an upper end of a first pressure chamber and a disk is installed on the inlet hole, such that the inlet hole is closed so as to prevent a pressure of the first pressure chamber from being continuously increased.
2. Description of the Related Art
Generally, suspension systems are installed in vehicles so as to improve a ride comfort by absorbing and damping a vibration or shock which is transferred from a road surface to an axle during driving. As one of such suspension systems, a shock absorber is used.
The shock absorber operates with a vibration of a vehicle according to a condition of a road surface. At this time, a damping force generated by the shock absorber is changed according to an operating speed of the shock absorber, that is, a high or low operating speed of the shock absorber.
A ride comfort and a driving stability of a vehicle may be controlled according to how to adjust a damping force characteristic generated by the shock absorber. Therefore, in designing the vehicle, it is very important to adjust the damping force characteristic of the shock absorber.
In this regard, an existing frequency-sensitive shock absorber or an existing pressure-sensitive shock absorber has a valve structure that realizes similar operational effects in terms of functions. However, parts for pressure sensitivity and parts for frequency sensitivity must be separately provided. Consequently, an increase in the number of parts and a rise in production cost are inevitable.
In particular, since such a problem causes an additional problem that the total length of the piston valve assembly is increased, there are many limitations to applying the conventional piston valve assembly to small- and medium-sized vehicles.